Why're you crying, Rae?

After thinking about it for a bit, Harry concluded that it must be because of the powers that the injectable granted. Maybe he was grateful towards Harry because of these powers maybe? Or maybe his reverence towards Harry increased when he realized that he had such godlike abilities which allowed him to grant powers to others?

Harry was bamboozled by this new revelation and was about to ask his system, Rae on what she thought the reason could be, when suddenly, Arnold got up and looked at him piercingly.

This slightly surprised Harry as he immediately put his guard up and was ready for him to attack him any second, when Arnold too bowed down respectfully and said, "This loyal subordinate greets His Majesty."

Harry felt extremely confused at this point because his words too were extremely similar to his brother's, except he did not degrade himself to a servant. I mean, even though a subordinate technically is a servant, it sounds much more classy.